Exterior Waterproofing
- Licensed & Insured
- 5-Star Rated
- Local Business
- Transferable Warranty
Exterior Basement Waterproofing That Stops Water at the Source
Exterior basement waterproofing keeps groundwater on the outside of your foundation, where it belongs. Across Maryland, Virginia, Washington DC, Pennsylvania, Delaware and West Virginia, many homes sit in dense clay and silt soils that soak up rain and drain slowly. Over time, the backfill packed against the walls holds water and presses it into cracks, joints and porous block. Exterior waterproofing replaces that problem with a sealed wall surface and a clear path for water to drain away, so it never reaches the inside of the basement.
This approach suits poured concrete and block foundations, and it is a strong fit for a finished basement that gets regular use, because the work happens outside your walls and floors. Best Buy Waterproofing has handled exterior waterproofing with its own in-house crews since 2017. Every project begins with a free inspection to confirm that exterior work is the right answer for your home.
Signs You May Need Exterior Waterproofing
These signs often point to water pressing against the outside of the foundation walls.
Leaks Through the Walls
Water seeps through block or poured walls during heavy rain or snowmelt.
White Chalky Residue
Efflorescence on walls shows water is moving through the masonry from outside.
Leaking Wall Cracks
Cracks in foundation walls that weep water after storms or each spring.
Damaged Finished Walls
Stained drywall, swollen trim or musty carpet in a finished basement.
Freeze-Thaw Damage
Spalling or crumbling masonry where wet soil freezes against the wall.
Saturated Soil Outside
Soggy ground or pooling water along the foundation after rain.
How Our Exterior Waterproofing System Works
Excavation Around the Foundation
Exterior waterproofing starts with excavation. Our crew digs along the basement walls down to the footing, exposing the outside face of the foundation. That lets us see what is happening to the wall itself, including cracks, failed coatings and areas where water has been getting through. We plan the dig around your landscaping, walkways and utilities and keep the work area organized from start to finish.
Removing the old backfill matters as much as exposing the wall. Dense, water-holding soil packed against the foundation is a major reason the basement leaks in the first place.
Foundation Membrane and Dimple Board
With the wall exposed and cleaned, we apply a waterproof foundation membrane to the outside of the basement walls. The membrane creates a continuous barrier against groundwater and seepage, so water cannot soak into the block or concrete. Cracks are addressed before the membrane goes on.
Dimple board goes over the membrane. Its raised pattern creates an air gap against the wall, protects the membrane during backfilling and directs water straight down to the drain at the footing.
Footing Drain and Washed Gravel
At the base of the wall, we install a footing drain, a perforated pipe set in washed gravel that collects water and carries it away from the house. We then backfill with washed gravel instead of the original clay. Gravel lets water drop quickly to the drain rather than sitting against the wall, which reduces hydrostatic pressure on the foundation.
The drain is routed to a discharge point away from the house, either by gravity where the lot allows or to a sump pump.
Sump Pump or Gravity Discharge
Collected water needs somewhere to go. On lots with enough slope, the footing drain can discharge by gravity. Where it cannot, we install a sump pump to move the water up and away from the foundation. Some homes benefit from a dual-pump setup for extra capacity.
We add a battery backup and alarm where a pump is used, so the system keeps working during storms that cut the power.
Our Exterior Waterproofing Process
Free Inspection
We check walls, cracks, grading, gutters and soil to find where water enters.
Your Recommendation
We walk you through what we found and what we recommend, with a firm price.
Excavate and Seal
Our crew excavates, applies the membrane, installs the drain and backfills with gravel.
Warranty Protection
Your exterior waterproofing system is backed by a transferable warranty.
Why Homeowners Choose Best Buy Waterproofing
Exterior waterproofing is a bigger project, and it should be handled by a team that does the whole job. Our own crews excavate, waterproof, drain and backfill.
- Serving homeowners since 2017: Our team has kept basements dry across the Mid-Atlantic since 2017.
- Licensed and insured: Licensed in Maryland, Virginia, Washington DC, Pennsylvania, Delaware and West Virginia, and fully insured.
- One in-house team: The same team handles waterproofing, foundation repair and crawl space repair.
- Free inspection and financing: Inspections are free, and financing options are available for qualified homeowners.
- Transferable warranty: Your exterior waterproofing warranty stays with the home if you sell.
What Affects the Cost of Exterior Waterproofing?
We do not price exterior waterproofing from a list, because every foundation, lot and soil condition is different. After your free inspection, you get a firm price based on what your home actually needs.
Wall Length
How many walls need waterproofing sets the length of excavation, membrane and drain.
Excavation Depth
Deeper basements mean more digging to reach the footing.
Foundation Condition
Cracks or damaged block may need repair before the membrane goes on.
Access and Obstacles
Decks, patios, porches, driveways and utilities affect how the dig proceeds.
Landscaping
Plantings and hardscape near the walls may need to be moved or protected.
Discharge Method
Gravity discharge or a sump pump with backup changes the scope.
Exterior Waterproofing FAQs
What is exterior basement waterproofing?
It is a system installed on the outside of your foundation. We excavate along the walls, apply a waterproof membrane and dimple board, set a footing drain in washed gravel and backfill with gravel. Water is stopped before it reaches the wall and is carried away from the house.
When is exterior waterproofing the better choice?
It is often the right fit for a finished basement you do not want to tear apart, for walls taking on water through the masonry, and for homes where you want water kept off the foundation entirely. Your inspection shows whether exterior, interior or a combination makes the most sense.
Does exterior waterproofing work on block foundations?
Yes. It suits both poured concrete and block foundations. Block walls are porous and have many joints, so sealing the outside face with a foundation membrane and relieving pressure with gravel and a footing drain helps keep water out of the cores and off the interior.
Will excavation damage my yard?
Some disturbance is part of the process, since we have to dig down to the footing. We plan the excavation around walkways, plantings and utilities, protect what we can and restore the grade when backfilling. You will know what to expect before work begins. Once the gravel backfill settles, the area can be replanted or restored as planned.
Do I still need a sump pump?
Not always. If your lot has enough slope, the footing drain can discharge by gravity. If not, a sump pump moves the water away from the foundation. When we install a pump, we recommend a battery backup and alarm so it keeps working during power outages.
Can exterior and interior waterproofing be combined?
Yes. Some homes take on water both through the walls and up through the floor. Exterior waterproofing protects the walls, while an interior perimeter drain relieves pressure under the slab. We recommend a combination only when the inspection shows both are needed.
Related Services
Popular service areas: Baltimore · Washington, DC · Arlington · Alexandria · Columbia · Frederick · Silver Spring · Wilmington · All service areas
Schedule Your Free Foundation Inspection
Find out whether exterior waterproofing is the right way to keep your basement dry. Book a free inspection for a clear recommendation, a firm price and financing options.
